The wacky final play of Saturday’s Ohio State-Northwestern game was great for the backers of the Buckeyes and horrible for the bookies – possibly to the tune of upwards of $100 million.

Northwestern, a 7- to-7 1/2-point underdog, had the ball at its own 8-yard line with five seconds to go, trailing 34-30. Quarterback Kain Colter completed a short pass to Tony Jones, who lateraled to Venric Mark as the Wildcats began what they hoped would be a “Stanford Band”-style miracle. But Mark’s subsequent lateral was errant, and the ball rolled into the end zone, where it was recovered for a touchdown by Ohio State’s Joey Bosa.

Just like that, a Northwestern cover became an Ohio State cover.

We’ll let the Vegas pros take it from here.

“Sometimes strange and unusual plays at the end of the game can cost the book or help the book, but what we saw on the final play of the Ohio State-Northwestern game no doubt cost the book a ton,” Kevin Bradley, sports book manager for Bovada.lv, told The Post in an email. ”Eighty-five percent of the money had come in on the Buckeyes. It made me sick for the rest of the weekend, but that’s the way she goes and I cannot dwell on it.”

So how much of a bath did the sports books take?

“The game was just another game for the most part and wasn’t an ‘over the top’ high-volume game — my estimate would be in that $3 million-$4 million dollar amount for the state of Nevada,” Jay Kornegay, director of the LVH Sports Book, told The Post, referring to the estimate Mark Rood of the MGM gave to the Sporting News. “Now remember, Nevada represents only 1.5-2 percent that is wagered in this country.”

The grand total changing hands worldwide (from bookies to bettors) was estimated at around $100 million by R.J. Bell of pregame.com.